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12v battery failure, Unable to access frunk

Gasaraki

Active Member
Oct 21, 2019
2,207
1,527
Syracuse, NY
I have my new Oct. 2021 ...MF299xxx Tesla Model Y. I already know to replace my 12 volt lead acid battery soon with an Ohmmu.

However, I also want be able to get into the frunk if the 12v system dies. Getting in at home isn't the problem; I'm worried about getting in when I'm out stranded somewhere. So I'd wrap up a small battery and put it into the tow-hook compartment (where the frunk leads are). However, I've seen recent reports that a 9 volt battery doesn't work anymore -- Tesla is insisting on 12 volts. And I'd like to use lithium since they last much longer than an alkaline A23 12-volt battery. But I can't find a 12v lithium. Two 6v lithium would also do the trick but are hard to come by. Would two 9v lithium batteries in series work, or is 18 volts too much for the frunk relay?

I have to imagine that this is already a solved problem. Does anyone know of a solution to this issue that we all might run into some day?

Thanks,

Scott

--

MYLR | Red ext | White int | 19" | 5 seats | tow | no FSD | made/delivered Oct 2021
No need to get lithium.


That's what I have stashed in the hole.
 
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e645824

Member
May 15, 2021
135
190
USA
Here are the piece-parts that I bought (see photos below):

I went with lithium because I just want to stuff it into the tow-hook slot and not have to worry about self discharge for many years. In about 7 years I'll remember to replace the batteries. Plus, my alarm system uses CR123 batteries so I already have a pile of them. I'll put it into a ZIP lock bag and attach it to the red/black wires. I put the gray wire nuts on (they aren't included). The box also has an on/off switch.

Scott

--

MYLR | Red ext | White int | 19" | 5 seats | tow | no FSD | made/delivered Oct 2021

IMG_0188.JPG



IMG_0189.JPG



IMG_0190.JPG
 
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android04

Member
Apr 1, 2016
515
526
Southeast Nebraska
Here are the piece-parts that I bought (see photos below):

I went with lithium because I just want to stuff it into the tow-hook slot and not have to worry about self discharge for many years. In about 7 years I'll remember to replace the batteries. Plus, my alarm system uses CR123 batteries so I already have a pile of them. I'll put it into a ZIP lock bag and attach it to the red/black wires. I put the gray wire nuts on (they aren't included). The box also has an on/off switch.

Scott

--

MYLR | Red ext | White int | 19" | 5 seats | tow | no FSD | made/delivered Oct 2021

View attachment 736159


View attachment 736160


View attachment 736161
Only problem I see with this is that it won't fit behind the tow hook cover (it might if you cut some of the high density foam around the hole). Have you ever looked behind the cover? The hole is about the same diameter as the tow hook threaded end. If you modify or cut into the foam and can get your battery box to fit, make sure to post some pictures.
 

N54TT

Member
Aug 14, 2018
978
766
NY
Only problem I see with this is that it won't fit behind the tow hook cover (it might if you cut some of the high density foam around the hole). Have you ever looked behind the cover? The hole is about the same diameter as the tow hook threaded end. If you modify or cut into the foam and can get your battery box to fit, make sure to post some pictures.

I was just going to say. Doesn’t look like that would fit behind the tow hook without some modifications. I have a bunch of cr123’s as well for my alarm and one of my LED flashlights. My other lights use 18650’s :)
 

e645824

Member
May 15, 2021
135
190
USA
Only problem I see with this is that it won't fit behind the tow hook cover (it might if you cut some of the high density foam around the hole). Have you ever looked behind the cover? The hole is about the same diameter as the tow hook threaded end. If you modify or cut into the foam and can get your battery box to fit, make sure to post some pictures.

It is quite cavernous in there. There is a small strip of black foam on the upper section that I removed, but otherwise there is plenty of space. Stick your finger in there and you'll see that the foam doesn't go up very far and it is easy to remove that small section. I have my battery box wrapped in a ziplock bag and I inserted it vertically in to the upper cavity. Here are some photos.

Scott

--

MYLR | Red ext | White int | 19" | 5 seats | tow | no FSD | made/delivered Oct 2021

IMG_0207.JPG



IMG_0209.JPG



IMG_0213.JPG



IMG_0214.JPG
 
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